The "best" method depends on your requirements.
- Does your client only want specific people to be able to access the epub, or are they OK with the public at large having access to it?
- Does your client want people to pay for the epub and so need a "shopping cart" service of some kind as well?
- Do they want DRM added to the epub (hiss, boo)?
- Do the people they are targeting have access to a PC, or do they need it to be possible to download the epub directly to the iPad via Wi-Fi?
When we know the answers to these questions we can give you the best (and probably contradictory
) advice.